Any step or offset where data that should agree does not. A tide bust appears as a vertical jump between lines run at different times; a heave bust as a mismatch between lines in different sea states; a draft bust between days when draft was logged wrongly. Busts are found in overlap, at crosslines and at junctions, and tracing their cause takes up much of a processor's day.
Big bust between the morning and afternoon lines, 18 centimetres, smells like a tide problem.
Also heard as
- tide bust
- heave bust
- vertical bust
Related terms
Crosslines
Survey lines run across the mainscheme lines so the two data sets can be compared as an independent check.
Tide correction
The adjustment that removes the height of the tide from measured depths so they refer to chart datum.
Static draft
The vertical distance from the waterline down to the transducer face while the vessel is at rest.
Junction
An overlap between a new survey and an adjoining or older survey, compared to check consistency.
Refraction
The bending of sonar beams as they cross water layers with different sound speeds, which distorts depths if uncorrected.